1. Field
The invention is related to an optical fiber cable that incorporates a ribbon-like structure in place of individual loose optical fibers.
2. Related Art
Two different types of optical fiber cables are ribbon cables and cables with individual optical fibers, either loose-tube, or tightly buffered. When designing and building networks, the advantages and disadvantages of these cables are weighed. Some of the advantages and disadvantages of these cables are listed below.
Advantages of ribbon cables include: (1) they allow for easy MPO connectorization; (2) they are relatively easy to mass splice; and (3) they provide for lower skew than cables with individual fibers. However, the design and manufacturing of ribbon cables can be more difficult.
Advantages of cables with individual fibers: (1) Lower PMD than ribbon cable; and (2) the design and manufacturing of the cables is easier relative to ribbon cables.
FIG. 2 shows an example of a conventional flat ribbon cable 4. This type of ribbon cable can be used by a user that requires low skew considering high speed transmission (e.g. 40 G or 100 G of parallel transmission). In addition, users that like the easy operation of MPO connectorization may use this type of cable. Two 12 fiber ribbons 5, 6 are stacked on top of each other in the cable 4. The cable 4 has an outer jacket 7. Aramid 8 is inside of the jacket and the inner shape is rectangular to keep the ribbon shape flat. This type of cable requires careful handling during the installation, because bending in incorrect directions may damage the fibers.
Conventional single-fibers cable are sometimes used by the users who prefer round and small cables. FIG. 3 shows an example of a single-fiber cable 13. Twenty-four fibers can be divided into two 12 fiber bundle units 11 by the binders. An appropriate amount of aramid yarn 12 is inserted between an inner pipe (e.g., a pipe 9) and an outer pipe 10 to protect the optical fibers from tension during installation and use. This type of cable allows a multiple installation into limited space because of its small diameter, light weight and flexibility.
It is an object of the invention to produce cable structure that has the advantages of both ribbon cables and single-fibers cables.